Materials of this kind have long been used for the manufacture of products of the kind in question, and are produced and marketed in the form of sheets or rolls. As fibre material, sulphite or sulphate pulp and also chemimechanical pulp, so-called CTMP, are used.
These products conventionally are produced in the wet way in that a fibre suspension is dewatered on a wire, pressed and dried. The dried web is reeled up or cut to sheets. As a starting material sulphate or sulphite pulp or chemimechanical pulp (CTMP) are used. The pulps made in this way are sold as so-called roll or sheet pulp.
The pulps alternatively can be sold in web shape after flash drying of the fibres. At flash drying the pulp fibres are dried in a fan drier. A pulp web is hereby pressed to about 50% dry solids content and torn so that individual fibres or fibre flocks are detached and thereafter dried when passing through the piping of the fan drier. The flash dried pulp then is pressed to bales. The resulting product has a high density, which offers transport-technical advantages compared with reel or sheet pulp. The transport economy of reel pulp, moreover, is made worse by the fact that cylindrical rolls have a low packing degree.
The chain of manufacture for soft absorption materials, such as napkins and towels, starts with the dry defibering or tearing of sheet, reel or bale pulp in order to detach the individual fibres bound in the sheet, web or bale. Due to their low moisture content, the pulp fibres then are relatively brittle. When there is a high bonding strength between the fibres in sheet, reel or bale pulp, the risk is great that the fibres will be damaged at the dry tearing and that much undesirable so-called fine material or dust will be formed. This is due to the fact, that a high bonding strength between the fibres implies high defibering energy. The producers of reel and flash dried pulp, therefore, are required to try to produce a product which can be torn as easily as possible, with weak fibre bonds in the product, which, however, must meet certain strength requirements for having good runnability in the defibering equipment. In order to obtain a product easy to tear, the roll or sheet manufacture in the commercial processes of to-day must increase the bulk of the product, which then also deteriorates its transport economy.
These problems are solved by the present invention.